Solution pen holder



FIG. 1 is a perspective view of the solution pen holder showing the new design;

FIG. 2 is a top view thereof;

FIG. 3 is a front side view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a bottom view thereof. 

The ornamental design for a solution pen holder, as shown and described. 